Starring: Kaley Cuoco, Johnny Galecki, Melissa Rauch, Simon Helberg, Jim Parsons, Kunal Nayyar
Genres: Comedy
The Viewing Party Combustion - S9-E21
Continuity mistake: At the end of the episode, Sheldon, Leonard, and Raj are shouting out the window to Stuart. They are shouting from the window in Sheldon and Leonard's living room, but this makes no sense as Stuart is outside the front of their apartment (you can see the apartment door as he cycles away). These areas are perpendicular to each other; in reality, the living room window would be around the corner of the building from where Stuart is.
The Extract Obliteration - S6-E6
Stephen Hawking: Do you like brain teasers?
Sheldon Cooper: Oh, I love brain teasers.
Stephen Hawking: What do Sheldon Cooper and a black hole have in common? They both suck. Neener, neener.
Trivia: During Season 3, the producers learned of a show called "The Theorists" in the country of Belarus that was a copy of this show. A lawsuit for copyright infringement would have been pointless since the production company for "The Theorists" was owned by the Belarus government. A lawsuit, however, was not needed because when the actors and actresses found out the show was a rip-off this one, they promptly quit and "The Theorists" was cancelled.
Answer: Because Raj's selective mutism seems to be caused by women that Raj sees (on some sort of conscious or subconscious level) as a potential sexual partner. An attribute that wouldn't apply to either his sister or mother.